Synephrine is named as the ephedrine’s bitter cousin. Thermogenic fat burners have been the main means of burning body fat for many years. It is also being called the ephedrine analog.
Although having a similar structure with ephedrine and having almost the same action mechanism and popularity, synephrine is by far not the most powerful thermogenic. Taking synephrine increases metabolism and calorie consumption.
The use of 50 mg synephrine, without physical activity, increases the body calorie consumption with 65 calories for the next 75 minutes, without showing any side effects.
Synephrine stimulates alpha-receptors which lead to an overall effect on the sympathetic nervous system. This leads to an increase in energy, endurance, strength, and cognition.
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Synephrine Overview
Synephrine is named as the ephedrine’s bitter cousin. Thermogenic fat burners have been the main means of burning body fat for many years. Their advantage is that most of them are effective.
Fat burners are complex products and are composed of several substances. Synephrine is among the most popular thermogenic ingredients. It is also being called the ephedrine analog.
Although having a similar structure with ephedrine and having almost the same action mechanism and popularity, synephrine is by far not the most powerful thermogenic.
What Is Synephrine
Synephrine is a natural substance and can be found in the bitter orange fruit, also known as Citrus aurantium. The natural form of synephrine is p-synephrine, which is an alkaloid component and a residual amine.
The use of synthetic synephrine dates back to the 20s of the 20th century. Synephrine was first isolated as a natural product in the early 60s with research on the composition of citrus fruits.
In the 70s researches deepened and synephrine was found in many other natural sources. The main natural source of synephrine is the bitter orange, the content of synephrine inside is 0.8-0.9% and a standard extract concentration reaches 7%.
There are also more concentrated extracts with a 30% content of synephrine. Synephrine is contained in all other citrus fruits, but its concentrations are significantly lower.
Synephrine can be also found in the Evodia plant, Zanthoxylum type. The bitter orange is a traditional fruit in Chinese traditional medicine as a tonic and appetite regulator.
It is also a popular dessert in Iranian culture. In Japan, it is used in celebrations for welcoming the New Year. Very small quantities of p-synephrine can be synthesized in the human body, as traces are detected in human urine and blood plasma.
P-synephrine is a natural form of synephrine, which should be distinguished from synthetic m-synephrine (neosynephrine, metilsynephrine). The synephrine structure is very similar to ephedrine one, but also chemically very similar to other substances which have the structure of phenylethylamine.
The differences, however, are also numerous. The change of the n-methyl group of synephrine with hydrogen atoms forms octopamine and the change of beta-hydroxy group forms n-metiltiramin.
How Does Synephrine Work
Synephrine can be synthesized in the human body. Animal studies have found that the synthesis of synephrine is implemented in the brain. Synephrine is a byproduct of the metabolism of tyramine.
Tyramine is metabolized into octopamine which oxidizes into synephrine. Oxidation of octopamine into synephrine and the oxidation of synephrine get implemented by MAO enzymes, as MAO-A is the most active one.
Most of the synephrine properties are associated with its function of agonist (promoter) of the adrenoceptors, preferably with an alpha-1 receptor over the alpha-2, as for their activation relatively high doses are needed.
Synephrine acts also on beta receptors but substantially less. Adrenoceptors get connected with the sympathetic nervous system which mobilizes the body's energy.
The Alpha-1 receptor is responsible for the shortening of muscles, vasoconstriction, and gluconeogenesis in the liver and adipose tissue, as well as the sweat stimulation. There is evidence that Synephrine has a partial impact on the 5-HT (serotonin) receptor.
After oral intake of synephrine, the plasma concentration peak occurs within 1-2 hours, while the half-life of the substance is about 2 hours.
It was also found that taking 150 mg of synephrine increases dramatically the levels of octopamine in urine and that exceeds the permitted quantity in doping control. Octopamine levels remain high in the urine within 24 hours after synephrine intake.
Proven and Potential Benefits for Human
- Taking synephrine increases metabolism and calorie consumption. The use of 50 mg synephrine, without physical activity, increases the body calorie consumption with 65 calories for the next 75 minutes, without showing any side effects. This action of synephrine is due to its ability to stimulate alpha-1 and alpha-2 receptors;
- Synephrine is classified as thermogenic, but researches on the thermogenic effect in humans are too little. Currently, there is no study showing that eating bitter orange by women increases thermogenesis;
- Synephrine stimulates alpha-receptors which lead to an overall effect on the sympathetic nervous system. This leads to an increase in energy, endurance, strength, and cognition. The intake of a higher dose of synephrine stimulates the nervous system in a short amount of time;
- The use of synephrine in the nasal cavity as a cream with a concentration of between 1-3% in patients with sinusitis leads to an improvement in their condition without irritation on the tissue;
- Potential anti-estrogen activity. There is a regulation of the relative weight of adrenal glands which may be due to the activity of the alpha-1 receptors and that increases vasoconstriction and reduces fluids in organs. The effects of synephrine are relatively moderate as ephedrine shows a statistically significant change.
Proven and Potential Benefits in Animals
- Tests on mice show that p-synephrine has an antidepressant effect, shortens the period of immobilization in stress tests by neutralizing the movements of the tail. Subsequent tests found that synephrine recovers the body from hypothermia and increases the release of noradrenalin to the brain;
- Liver function tests in rats have shown that the use of an extract of bitter orange and p-synephrine enhances glycogenesis and lipolysis if taken in moderate doses. At high doses, however, p-Synephrine has its impact but the extract shows the opposite effect - namely suppression of metabolic processes.
Side Effects
Taking p-synephrine does not result in an increase in blood pressure while taking the fruits of bitter orange increases it. The various extracts have shown mixed results.
An extract with a lower content results in an increase in blood pressure while the patented Advantra-Z (30% synephrine) does not show any change. All extracts lead to an increased heart rate.
P-Synephrine shows no side effects and is safe for use. Metilsynephrine, however, can show signs of toxicity. Tests in animals have shown that the dose is 400-500 mg/kg weight is highly toxic.
Lower doses over a prolonged period of time show no intoxication. High concentrations of synephrine, like the tyramine metabolite, are associated with the occurrence of acute headaches and migraines.
It has been found that people with migraines have larger amounts of synephrine in their blood plasma. Although theoretically possible, oral intake of synephrine can worsen the occurrence of headaches.
It is possible that a higher dose of synephrine can result in a positive doping test. Taking 150 mg synephrine enhances the separation of octopamine in the urine and that is prohibited.
On the other hand, it was found that intake of 54 mg of synephrine (900 mg extract) does not lead to a positive doping test. Pregnant women are not recommended to use synephrine because it can cause contractions.
Not recommended for use by nursing mothers. People suffering from arrhythmia, as well as suffering from glaucoma, are not recommended to use synephrine because it may worsen their condition.
How to Combine Synephrine
- Synephrine is a quality stimulant and a moderate thermogenic. In order to stimulate the nervous system, synephrine is combined successfully with caffeine, as both stimulants show synergistic properties. Other attractive synergists are yohimbine, phenylethylamine, and Evodia.
- Used as a fat burner, synephrine is successfully combined with green tea, caffeine, yohimbine, forskolin, and others.
- Synephrine has a positive influence on the body's metabolism by stimulating the consumption of calories. 50 mg synephrine increases the number of burned calories by 65. The addition of bioflavonoids enhances this effect. If added 600 mg naringin, the burned calories get 129 kcal and an additional 100 mg hesperidin can boost the number to 183 kcal. The combination of synephrine with drugs against depression of the MAOIs class is not recommended.
Where Can We Find Synephrine
Synephrine is available as a nutritional supplement but nowadays is still not unpopular. In addition, synephrine can be found as a standalone product or as part of a complex formula.
Separate forms of synephrine can be found as extracts or bitter orange powder. The most highly concentrated extracts contain up to 30% synephrine. The patented Advantra-Z is such an example.
The standard capsule dosage is 30-33 mg extract of bitter orange with 10-20 mg synephrine. Conventional versions with bitter orange powder traditionally do not indicate this concentration.
Complex products containing synephrine are pre-workout formulas or thermogenic fat burners. Synephrine is part of the pre-workout concentrates. One of the most famous is BSN Hyper FX.
Other famous synephrine thermogenics are Twinlab Ripped Fuel, BSN Hyper Shred, Nutrex Lipo 6x and Lipo 6 Black. When synephrine was introduced to the market as a product for fat burning, it was compared a lot with its far more powerful cousin - ephedrine.
Although not as close to the action and efficiency of ephedrine, synephrine has advantages that should not be underestimated. Synephrine has a relatively modest effect but in combination with other similar ingredients, it can show a maximum effect on the desired goals.
Although synephrine is far weaker than ephedrine, a person should be careful with it because every thermogenic has its risks.
